I switched from PC to MAC last October and have been happy with almost everything except the performance and experience with Parallels Desktop 9. I hardly have to use it, but each time I do, the experience is frustrating and horrible. I've been able to do 95% of my work on MAC, but there are sometimes I need windows such as remote desktop to access apps that sit on another machine (trust me, there's no other way around this. Even on windows, I had to RDP to those systems). When the performance was not that great, I just assumed it was the RDP experience. However, if I use Microsoft Office in Parallels AND coherence mode, at some point it shuts down the entire VM - always happens. If Office is used without coherence, maybe I get 30-60 minutes before the screens starts pixellating or going nuts and I have to restart. The MAJOR problem I have with Parallels is the FAN NOISE. In OSX alone, I could have many apps running simultaneously and everything is super quiet. I turn on Parallels and even with ONLY Firefox running, the fan comes on and it's very frustrating. It always happens. The fan is not as loud as my windows, but when you go from whisper quiet to a persistent noise, that's just hard to ignore. I have a late 2013 15" MBP with 16GB ram so it should not be a problem with resource. Maybe it's my own ignorance/poor settings, but I've heard not to use more than 4GB ram for windows as it could negatively impact the OSX session. I'm using Parallels Desktop 9, running windows 8.1. I have 2 CPUs and 4GB RAM allocated. My optimization settings are: Please help. Thanks!